dolby



(No Model.) 2 Sheets-Sheet 1.

T. e. F. DOLBY.

SHEET METAL CAN No. 331,482. 'Pa-tented Dec. 1, 1885..

WITNESSES: HEWZNTOR;

Wm M M N. PETERS. Fholo-Mhogmpher. Washinglun, u.c.

(No Model.) Sheets-Sheet 2.

, T. G. P. DOLBY.

SHEET METAL GAN- No. 331.482. Patented De0. 1, 1885., F1 g. 5

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WITNESSES: NvE NTOR: o) y w @2 5 41 by Ins ,flttomeys,

ivirnn fl'ra'rns Parana FIQEO THOMAS G. F. DOLBY, OF LOKDON, ENGLAND.

SHEET-Ni ETAL CAN.

SPECIFICATION forming part of Letters Patent No. 331,.82, dated December 1, 1835.

Application filed April 25, 1884. Serial No. 129,267. (No model.)

To aZZ whom it may concern.-

Be it known that I, THOMAS G. F. DOLBY, a subject of the Queen of Great Britain, and a resident of London, England, have invented certain Improvements in'Oans, of which the following is a specification.

My invention relates to the construction of the closing devices of sheetanetal cans; and the object is to improve the construction of the can-top and cover so that the can may be hermetically closed without the necessity of using solder, rubber, or other packings, sealing-wax, 850., and its cover be held firmly in place.

My invention will be fully described hereinafter, and its novel features specifically defined in the claims.

In the accompanying drawings,wherein my invention is illustrated, Figure 1 is a transverse section ofthe can-top, cover, and retaining-screw ring, all in place as when the can is closed. Fig. 2 is a plan of the same, a portion of the screw-ring being broken away, the bettcr to show the cover in plan. Fig. 3 is a crosssection of the can-top alone. Fig. 4 is a crosssection of the cover detached. Fig. 5 illustrates a slight modification, which will be hereinafter described.

A represents the body of a can, which may be of any shape, but it is here represented as square.

B represents the plate forming the top of the can. In this plate is formed a circular opening, around the margin of which is formed a pendent elastic flange, b, which is slightly conical. G is the cover,wl1ich has an upturned marginal flange, a, slightly conical and made to fit closely and accurately into the flange b on the top B. I prefer also to formon the upper edge of the flange 0 of the cover a slight projecting flange, d, which will catch on the top plate and prevent the cover from being pushed down into the can. If the work is properly done, however, this flange d is not absolutely essential. I also elevate the center 6 of the cover, as shown in Figs. 1 and 4, for reasons that will be hereinafter explained. The conical flange b on the can-top and the conical flange c on the cover being both truly made and slightly elastic, the cover fits into the opening in the can in the manner of a cork or stopper, and adapts itself by elasticity to any slight distortion due to warping in the operation of solderinga characteristic difficulty in all sheet-metal construction. If desired, a slight film of some soft wax may be applied to the exterior surface of the flange c as a precaution and to make sure of an absolutely air-tight joint. This will not prevent the ready and easy removal of the cover. The curving of the flanges b and 0 should be such as to prevent the sticking of the cover so that it would be distorted in removing it. Only one of the flanges b or 0 need be elastic.

In order to prevent the accidental disturbance of the cover in transportation or handling, I provide the oan with a precautionary retaining device, which I will now describe.

Mounted on and secured to the can-top B is a raised flange or ring, I), which is internally screw-threaded, either by forming the thread in the thin sheet metal, by spinning or pressing, as shown, or by cutting in the usual way where thicker metals are used.

E is a screw-ri1ig,which is externally screwthreaded to fit the screw-thread in D, and provided with an inturned flange, g, which is slightly depressed at its inner free margin. This ring E is screwed down in D until the depressed edge of flange g rests on the raised central part, c, of the cover 6. Thus the elastic flange g, pressing on the somewhat elastic part c of the cover, presses the cover down elastically, and tends to expand the flange c of the. cover and make it fit more tightly in the aperture in the can. This more effectually prevents the accidental disturbance of the cover, and at the same time assists in keeping the cover tightly in place and level. I provide the cover with a ring, h, to enable the former to be removed, and I provide the ring E with a cross-handle, 1;, whereby the said ring may be screwed down tightly.

The object in raising the central part, c, of the cover is to bring it up so that the inturned flange of the ring E may rest upon it without unnecessarily extending said ring downward, and the construction shown I think imparts more elasticity to the flange c.

In Fig. 1 I have shownthe flange b as forming a part of the ring D, and this is the way I usually construct it; but it may be formed on the can-top B, as in Fig. 3.

In Fig. 5 I have shown in cross-section a modified construction, which I will describe. In this construction the flange b is upturned instead of pendent, and is exterior to the can, and the flange 0 on the cover is pendent. The flange b is for convenience formed on the ring D, and the flange g rests on the bead formed on the cover between the flange c and the depressed center 6.

I do not broadly claim the stopper-like construction of the cover nor the employment of a screw-ring, as these are both WGllkDOWil devices; but

What I claim is The combination, in a sheet-metal can, of the can-top, provided with an aperture and a conical marginal flange, b, the cover provided with a conical flange, 0, and a raised central part, 6, the screw-threaded flange or ring D, and the screwthreaded ring E, provided with an inturned flange, g, all arranged substantially as herein set forth.

In testimony whereof I have hereunto signed my name in the presence of two subscribing wit- 

